自动饮水机已经普遍用于车站、学校等公共场所,它的简化电路图如图所示,电热丝电阻分别为R1、R2,请根据说明书提供的信息计算(水的密度ρ水=1×103kg/m3,水的比热容C水=4.2×103J/kg℃)
饮水机参数
热水温度:≥90℃
热胆容积:2L
额定功率:1000W
保温功率:40W
额定电压:220V
频率:50Hz
The upset mother thought to herself, “If only I ______ what's going on in my little boy's head right now.”
下列各项中没有错别字的一项是( )
When people ______, they take air into their lungs (肺部) and let it out again.